[PATCH rcu 3/6] rcu: Provide rcu_barrier_cb_is_done() to check rcu_barrier() CBs

[Paul E. McKenney]

This commit provides a rcu_barrier_cb_is_done() function that returns
true if the *rcu_barrier*() callback passed in is done.  This will be
used when printing grace-period debugging information.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
 kernel/rcu/rcu.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index f035fd4e579b4..feb3ac1dc5d59 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -252,6 +252,11 @@ static inline void debug_rcu_head_callback(struct rcu_head *rhp)
 		kmem_dump_obj(rhp);
 }
 
+static inline bool rcu_barrier_cb_is_done(struct rcu_head *rhp)
+{
+	return rhp->next == rhp;
+}
+
 extern int rcu_cpu_stall_suppress_at_boot;
 
 static inline bool rcu_stall_is_suppressed_at_boot(void)
-- 
2.40.1